PCR Identification And Drug Sensitivity Assay Of Chicken Shigella Isolates From Some Regions Of Henan Province

In order to provide reliable basis for accurate diagnosis and effective control of chicken Shigella disease, assays including pathogen isolation, identification and drug resistance were carried out to 156 samples of 114 chicks suspected having Shigella diarrhea from 98 chick farms in 18 regions (such as Zhengzhou, Nanyang, Zhoukou et al.) of Henan province.34 isolates of chicken Shigella dysenteriae were identified from 273 isolate of bacteria with morphological, biochemical, serological, PCR and pathogenicity assays.34 isolate of Shigella showed drug resistance to 14 kinds of antibiotics in a vary degree.1. Bacteria isolation and culture, morphology staining and biochemical tests 34 strains of Shigella were isolated according to characteristics of bacteria culture, staining and biochemistry. Isolation rate were 11.89%(34/286)2. Chicks infected with the Shigella isolates showed 80% morbidity and 0-100%mortality in pathogenicity assay. This indicates that the 34 Shigella isolates were pathogenic to chick.3. Serological identification:Result of plate agglutination test with multivalent Shigella-positive serum were positive.This further confirmed that the isolates were chicken Shigella.4. Drug sensitivity assay:Drug resistance of the 34 chicken Shigella isolates to 14 antibiotics (including cefazolin, Roxithromycin, gentamicin, ciprofloxacin, etc) were confirmed by Kirby-Bauer method. Results as fellow, all the 34 Shigella isolates showed serious resistance to roxithromycin, drug-resistance strains accounted 100% (34/34) of the Shigella isolates, drug-resistance rate to cotrimoxazole and norfloxacin reached 97.1%(33/34), drug-resistance rate to ciprofloxacin was 94.1%(32/34), drug-resistance rate to chloramphenicol 88.2%(30/34), the 34 Shigella isolates showed different degrees of drug resistance to other antibiotics, resistant strains accounted for 23.6%(8/34)-88.2%(30/34)of total isolates. All the results showed Shigella isolates from different regions showed various degree of drug resistance., isolates from the same region showed significant differences in drug resistance.5.All the 34 chicken Shigella isolates were identified positive by PCR method with ipaH gene of Shigella.